Wireless telegraph apparatus



H. E. HALLBORG .ET AL WIRELESS TELEGRAPH APPARATUS Filed June 6, 1921 4 Sheets-Sheet 2 AUDION 2Nu.STAGE AMP.

AUDION 15T. STAGE AMF!A SPARK TRAN SMITTE unAuoQG.

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WITNESSES A TTURNEYS July 2s, 1925. 1,547,2i5.

n H. E. HALLBORG ET AL WIRELES S TELEGRAPH APPARATUS l 'Filed June 6, w21 4 Sheets-Sheet 3 5 Juy 28, 1925.

H. E. HALLBQRG ET AL wRELEss TELEGRAPH APPARATUS Filed June e, 1921 4 Sheets-Sheet 4 15 H BHALUBORG.

WITNESS/:"8

Patented July 28, 1925.l

UNITED STATES PATENT"""oFFIcia.

'HENRY- EMMANUEL HALLBOR-G, 0F NORFOLK, VIRGINIA,A AND AROLD REDMORE i MILLER, OFWASHINGTON, DISTRICT 0F COLUMBIA.

lTIRELESS TELEGRAPH APPARATUS.-

Application led June 6,

To all whomjt may concern Be it known -`that we, HENRY EMMANUEL HALLBORG and HAROLD REDMORE MILLER,

4citizens ofthe United States, and residents of Norfolk, in the county of Norfolk and State of Virginia, vand Washington, 1n the District of Columbia., respectively, have inventedv certain new and useful Improvements in Wireless Telegraph Apparatus, of i which the following is a. specification.

Ourjnvention relates to improvements 1n wireless telegraph4 apparatus, and it consistsfin the constructions, combinations and modev of operation herein described and claimed.

The fore-most 'object of the invention is to provide means in a wireless telepraph apparatus for rendering the telephones 1noperative While thekey is depressed in the transmitting position. t

.Ap-further object of the'invention 1s to provide a wireless telegraph apparatus, including a receiving system' -which embodies a low reactance condenser for short circuiting the'telephones when the operating key is depressed tov the transmittlng position.

Aff-further, but secondary, object of the invention is 4to provide an improved break key, the special construction of which plays an important part in the operation .of the improved wireless apparatus.

' Other objects and advantages will appear in' Vthe following specification, reference being had to the accompanying drawings` in 'Figure l is a diagram of a wireless tele :graph apparatus, illustrating both the application ofthe shunt-condenser and the 1mproved manual break key, l

`.Figure 2 is a diagram illustrating the aplication of the aforesaid elements -`of the invention to a spark system having a vacuum tube and amplifier system of'reception,

Figure 3 is a side elevation of the manual break key used in connection with the improved Wireless'apparatus, l Figure 4 is a, side elevation illustrating the main contact` in detail, parts being shown insection for this purpose,

Figure 5 is a section on the line 5 5 of Figure 3, clearly 'illustrating how the lifting screws for the auxiliary contact levers are mounted on the main key lever,

Figure 6 isa cross 'section on the line 6-6 the transmission of signals.

1921. Serial No. 475,278.

of Figure 3, illustrating the main trunnion of the key lever, A i

Figure 7 is a cross section on the line 7-7 of Figure 3, illustrating the auxiliary trunnions of the auxiliary contact levers,

Fi ure 8 is' a detail section taken substantially on the line- 8-8 of Figure 10, illustrating the auxiliary contact lever in .the telephone shunting condenser circuit,

Figure 9 is a detail cross Section on the line 9 9 of Figure 8,`illustrating the contacts ofthe telephone shunting condenser circuit,- p

.igure 10 is a plan view of the break key, an

Figure 11 is a detail sectional view illustrating a modification of the main trunnion in Figure 6, wherein the key lever is mounted on adjustable screws which are fixed by jam nuts.

As indicated in the general objects of the invention above, the foremost purpose of the invention is to provide means to be used in connection with any of the u,well knownl wireless telegraph systems, for deadening the sounds in the telephone, especially during the transmitting operation, so asto entirely obviate theprevailing annoyance of the operator. This feature of the invention is easily and Well explained in connection with Figures l and 2 of the dra-wings."` The apparatus in Figure -1 embodies a vacuum -tube transmitter, a vacuum tube detector and amplifier, while the transmitter-in the 'loA apparatus in Figure 2 is of the spark type but also embodies a vacuum tube detector and amplifier.

Attention is' The condenser 63, on the operation of which much importance is attached as indicated above, is connected in shunt around -the telephones 64. A wire 65 runs from one side first directed to Figure 1. i

ofthe condenser to the tip 60 of the manual break key illustrated in Figure 3 et seq., the companion contact tip 5 9 being connected by the wire 66 to one side of the telephones 64:. A wire 65a is connectedbetween theremaining sides of both the condenser and telephones and this wire joins the battery B which furnishes current tothe plate circuit again -referred to below.

An ACgenerator 4 furnishes current for 68 designates the receiver of the apparatus in a general connected by a wire S2 to the secondary winding S3 of the transformer S4, which supplies current 'tor the plate circuits. Vhen the main contact A is opened, the current for the plate circuits 1s cut ofi, and the vacuum tubes 76 and 77 therefore have no detrimental effect on the reception of sig'- nals. The schedule of operation of the ap` paratus 1n Figure l 1s as follows:

Conl mots Sending position I Receiving position A Closes generator 4-platc Opens generator-plate trzinstransformercircuitisupiornicr circuit cutting o plying voltage to plates of plate voltage. transmitting tubes 7G. 7T.

a. Connects condenser (i3 of Diseonnects condenser maklow reaetancc in shuntA to ing phones operative for telephones G4. reception with amplifica- I tion, b Short circuits primaryi of Cuts iri primary of receiver completing receiving cirrecciver 68. completing cuit.

transmitting circuit.

,ftector G9 and Afirst and second stage amplitiers and 7l are .substantially alike in both cases, as are also ,the various Wiring arrangements in'eonnection wiitlii the manual break key. Similar reference characters indicate like parts in both diagrams.` The operation of the spark vsystem may be readily followed in the following' sc'lliiediii'le :V

Particular attention is directed to the purposes and method of-operation of the shunt condenser 63. The receiving circuit employing a vacuum tube for the purposes of either detecting or amplifying the received signal, requires a current of small value to be maintained through the telephone continuously during the entire time that the device is in oper/ation. The response' in the telephones is caused by signal Waves superimposed on this steady current. The steady current is furnish-ed by the battery B of the plate circuit.

Experience has demonstrated that it is impractical to dcaden the telephones during the time that the key is closed in the transmitting position, by opening any part of 'the audion or receiving circuit which would produce the desired effect, because the disturbance resulting especially with an ampli lied signal to the extentI of two or more stages as shown for example in Figures l and 2, produces noises in the telephone which seriously annoy the operator. By Vvmeans ofthe condenser G3, the desired effect is obtained. lithout disturbing in any way the rest of the receiving circuit, this condenser by-passes from the telephones all other than the steady currentfroni the battery B," previously mentioned, when it (the condenser) is connected around the tc ephones.' The closure'of the auxiliary contact fr of the key, completes the shari circuit. The effect of the completion of this circuit is to render the telephones insensitive from induction during the time that the key-is depressed and the bypass circuit is closed, and to place the receiving circuit in instant operation immediately that the key is released andthe by-pass circuity again opened. All this is done Without causing any disturbances which would annoy the operator.

Particular emphasis is laid on this feature which allows the break-key principle to be applied to modern receivingA circuits employing amplifiers to enablethe reception of Weak signals. The condenser 63 must have a very low reactance as compared with the telephones, so that the currents may readily v reception.

The timing of the engagement of the tips 59 and 60 of the auxiliary contact a whichV complete the shunt condenser circuit and the receiver' protective circuit relative to the main contact, is' important and must: be adj usted slightly in advance of the latter; in other' words, the shunt condenser contact a closes'` liirst and openslast.. Actual details of construction oit the manual break key itself are not of great importance, so long asthe conditions described above are complied with. However, thekey illustrated in the accompanying drawings' is considered Well adapted to the purpose of the invention and although by no means claimed as the only construction or mechanical arrangement by which the principles of the invention can be satisfactorily carried out, is nevertheless described 4in detail so that the reader may obtain a good idea as to how it Works.

The base 1 is composedA of suitable insulatple, to ya table by means of the brass studs 2 and 3'.- These studs are chieiiy employed for connecting the 500 cycle generator 4 in Figure 2 to the main key lever, through the wire connections 5 and 6 which are secured at the washers and check nuts 7 and 8.

For the purposes of subsequent description, the key comprises three principal contacts: The main contact A, the telephone shunting condenser auxiliary contact a, and the re-- ceiver primary auxiliary contact b. The main contact A includes the contact base 49 of brass, into which the upper end of the front stud 2 is sweated'so as to make a permanent connection. The end of the stud is drilled and tapped so that the silver contact 10 may be screwed into place.

At the rear of the base 1 the stud 3 passes` up into the trunnion 11 of the maingkey lever, where it is secured by being sweated into place: The trunnion is held in position by Jthe screws 12 which pass up from be.

.neath, the heads occupying counter bores as shown in Figure 6. The trunnion 11 is composed of a metallic composition. A

In the center of the base are the auxiliary" contact trunnions 13 and 14 of the contacts a and b respectively, both being made of a metallic composition and secured to the base 1 by screws 15 as in Figure 7. Farther front are the auxiliary contact bases 16 and 17, both made of a metallic composition, and each secured by a screw 18 as shown in one instance in Fi 're 3. The description of The main key lelver 19 is now in order. This key lever, as well as the other movin parts, is intended to be made of-metal o low specific gravity, as `for example, aluminum, or compositions-thereof, in order to reduce the mechanical inertia of such moving parts. This key has a button 20 of insulating material and a guard disk 21 also of insulating material. There is a down-v ward protuberance 22 near the front, drilled and tapped for the reception of the silvercontact 23 which coacts with the 'other silver contact 10, previously described. These two are `the onlysilver contacts; the others are made of copper. Obviously, other material may'be employed as may be deemed expedient for any of the contacts. i

Bosses 24 on the main key lever carry insulating plugs 25 in which brass bushings 26, 27 are mounted and suitablyl secured against turning. These bushings carry the lifting screws 28, 29, which have knurled heads 30 at the top and shanks 31 with heads 32 at the bottom. The lifting screws are adjustable in the bushings andthe adjustments are fixed by check nuts 33.

A central enlargement 34 carries the spring screw 35 which has a knurled head 36 at the top for turning. The main spring 37 is adjusted in tension by the screw 35. The adjust-ments are fixed by the check nut :$38. The base of the spring seats in a hole 39 in the insulating base 1. The standard 40 of the main trunnion 11 carry a shaft 41 on which the main lever rocks. The ends 0f the shaft are fixed at 42. The copper braid connector 43 secures a good electrical connection between the movable key lever and the .metallic main trunnionv 11, from whlcli'current is conducted by way of the rear stud 3 .as already explained. Screws 44 secure the connector to fthe key leverand trunnion respectively. 'he subscrew 45 fixes the degree of vibration of the main key lever. The lower end o-f thescrew strikes'the pad 46 on the trunnioiL/i'f' Like the other screws of the key lever, it/f'has a knurled head 47 and a check nut 48 f or iix ing the adjustment.A

The auxiliary contacts a and b comprise levers 49 and 50 fixed by means'vof screws' 5 1 on spindles 52 which are journalled in the standards '53 of the auxiliary trunnions 13 and 14 mentioned before. Copper braid connectors 54 are fastened to the auxiliary levers by the screws 51 which secure the latteil to thespindles 52, and tothe auxiliary trunnions 13 and 14 by means of screws 55, forthe purpose of making goodvelectrical connections between the movable levers and trunnions.

The ends of the auxiliary levers are bifurcated at 56, as shown for example in Figure 8, to str'addle the Shanks 31 of the lifting screws 28, 29. When the main lever 19 is raised bythe spring 37 upon releasing the button 20, the auxiliary levers will in turn be raised through engagement of the heads 32 of the lifting screws with the underside of the auxiliary levers at the bifurcations.

r V Springs o7 engaging the spring sciews o8,

urge the copper contacts 59, 60 and 61, 62, respectively of the auxiliary levers 49 and 50intoengagement. These contacts are respectively screwed into the auxiliary levers and into the bases 16 and 17 as shown in Figures 3, 6 and 8.

The operation is doubtless obvious enough to the reader. Upon release of the operating button 20, the main spring 37 will press upwardly on the main key lever 19, rocking y i usual send-receive switch.

various contacts is easily regulated by the adjusting means shown in connection With the individual contact5 so that such contacts may all open together or in sequence, as may be desired. The key is normally adjusted tor the following sequence.

a-b-A A-b-a The manual key performs the dualfunction of transferring the circuits from sending to receiving, without the medium of the lt permits the reception of a highly'amplified signal With- Order of closing Grder of opening out interference from the local transi'nitter,

and it tends to speed up traliie by making the telephones instantly responsive whenever the key lever 19 is released. The main and auxiliary contact levers may be made of metal of lovv specific gravity, as, for example, aluminum and-its compositions, i'n order to reduce the mechanical inertia in 'the operation thereof.

Attention is directed to Figure 11. 1nstead of mounting the main key lever 19 on a shaft 41 as in Figure 4, it may be mounted on cone-pointed screvvs 7&1, which lare capable of adjustment and are fixed in s uch adjustment by means of jam nuts 75. The. conical points of the screvvs4 enter corresponding recesses in the sides of thegkey lever. It is readily seen with what ease the key can be disassembled` particularly when the arrangement 74 and 7 5 in Figure 11 is employed.

In conclusion, it may be stated that the manual break key described above, is related to our co-pending application for Letters Paten-t for Wireless telegraph apparatus, filed October 25, 1920, Serial No. L119,231, which describes a relay for receiving amplified signals from either a damped or undamped Wave distant transmitter Abetween the dots and dashes of the transmitter of the local station. Both instruments, i. e., the relay of the co-pending application and the break key herein disclosed, are alike in this, that both receive the signals when the key lever is released, thereby speeding up the handling of messages both outgoing and incoming.

There is another distinction between the two devices mentioned; the quick-actingbreak key of the co-pending application operates as a result of the manipulation of a hand key which is associated therewith, while in the present instance, those instrumen-talities which produce the functioning ofthe invention, are embodied directly in the hand key, and it is for that reason that the present invention is entitled a manual break key.

It is regarded as import-ant to here define the major defects of break keys in common use, Which have been observed to be as follovvs: (a) sluggislmess of operation, (o) noisy reception, (c) rugged contact detector required, (d) inaccessibility and unreliability of adjustment, (e) frailness of construc- `tion, (f) multiplicity of contacts. become more evident to the reader from the description bcloiv, that these defects are entirely cured in the improved break key, and.

in order that the construction and operation may be understood, the description is directly entered.

Thile the construction and arrangement of the improved Wireless telegraph apparatus as herein described and clainied, is that of a generally preferred form, obviously modifications and changes mayv be made without departing from the spirit of the invention or the scope of the claims.

1. A break key, comprising a main contact lever, with means normally opening it;

opening movement of the main leverv under the influence of its opening means, and means embodied in saidl auxiliary leveropening means for regulating the order of opening movement of said levers.

3. A break key, comprising a main lever with contacts, and resilient means normally forcing a separation; a plurality of auxiliary levers with contacts, and resilient means normally forcing engagement; means carried by the main lever for forcibly separating the auxiliary lever contacts against the infiuence of their resilient engaging means when said main lever contacts are separated by the influence of its resilient means; and means embodied in said separating means for adjusting them in respect to 'the main lever to variously regulate the order of said`forcible separation. y

4. A break key, comprising an insulating base, a metallic trunnion with standards piv- 'otally supporting a main contact lever, a

engagement, and independent adjustable means carried by the main lever, operatively associated with the auxiliary levers for forclbly separating the auxiliary contacts against their resilient means upon the separation of the main lever contact under the influence ofA its resilient means.

5. In a break key, an insulating base,l

"able key lever with a corresponding contact.

6. In a break key, a main key'lever with aboredvenlargement, an insulating plug .fitted into the bore, a metallic plug carried by the insulating plug, a lifting screw 'adjustable in the metallic plug, and means for fixing the adjustment of sald screw.-

`7. In a break key, a main key lever withV an insulativelymounted lifting screw including a reduced shank and a head, and anv auxiliary lever having a bifurcated end 0c- -cupied by the shank, liftedl after a predetermined movement ofthe main key lever when said head en a s theauxiliary lever.

HENRY 'HAROLD lREDMORE MILLER.

NUEL HALLBORG. 

